Networked computers represent significant targets of opportunity for both recreational and malicious hackers, viruses, worms, scripted attacks, etc. Hacks and hackers are called different things and have different levels of sophistication, but in almost all cases successful hacks gain access to a computer through its network interface. This is particularly true when the network interface is coupled to the Internet. Computers supporting Internet Protocol (IP) and other IP network nodes, are identified by their IP address. Each network interface may support up to several thousand ports. To help manage security of the network interface, a firewall may be employed which processes data arriving for individual ports. Some ports such as port 80, commonly used for HTTP protocol support, may be assigned or opened to allow traffic to pass through to a corresponding service, for example, running on a web server, that manages HTTP traffic. The firewall may close all other ports to restrict outside traffic from gaining access to the network.
In closing all other ports, the firewall may give information to a potential hacker about which ports are closed relatively quickly, thereby allowing them to focus attacks on the open ports.